JPH07171762A - Polishing device - Google Patents

Abstract

PURPOSE:To reduce the discharge of dust into the surrounding air from a device and improve polishing accuracy. CONSTITUTION:A rotatable first column 20 is erected at the side of a surface table 11. A second column 26 is engaged in the vertically movable state with the first column 20 and moved vertically by an elevating drive part (air cylinder) 30. The second column 26 is provided with an arm 34, and a polishing head 40 is fitted to this arm 34. The surface table 11, the first column 20 and the polishing head 40 are driven by direct-coupled or built-in motors M1, M2, M3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for polishing a work such as a semiconductor wafer by polishing or the like, and more particularly to a polishing apparatus capable of taking measures against dust generation and improving polishing accuracy.

[0002]

2. Description of the Related Art In a polishing apparatus, a polishing platen is rotated and a workpiece such as a semiconductor wafer is attached to a polishing head provided so as to rotate in opposition thereto. Is pressed against the surface of the workpiece, and the polishing head is moved in the radial direction of the surface plate so that the entire surface of the workpiece is polished more uniformly.

In a conventional polishing apparatus, a polishing head is attached to a revolving arm so as to be movable up and down, and an up-and-down drive unit attached to the revolving arm moves the polishing head up and down and controls a pressing force against a surface plate to rotate the polishing head. Is provided from a motor provided on the swivel arm or a frame on which the swivel arm is mounted via a rotation transmission mechanism that also serves as a speed reduction mechanism such as a belt. It was designed to be performed from a motor via a speed reduction and rotation transmission mechanism such as a belt or a gear.

[0004]

By the way, in the structure in which the polishing head is attached to the revolving arm so as to be movable up and down, the relative movable part is located near the surface plate, and a workpiece such as a semiconductor wafer is rubbed by the metal abrasion powder. Highly likely to be contaminated, and
The entire apparatus has a structure in which dust is easily released into the atmosphere and has a drawback that it is likely to pollute the surrounding environment.

An object of the present invention is to reduce the amount of dust emitted from the apparatus to the surrounding atmosphere and to improve the polishing accuracy.

[0006]

In order to achieve the above object, the present invention provides a polishing platen which is horizontally arranged; a platen rotation driving means for rotatingly driving the platen; and an upper part of the platen. A polishing head that is rotatably disposed facing the surface plate; an arm that rotatably supports the polishing head; a polishing head rotation drive unit that rotationally drives the polishing head; and the polishing head on the surface plate. On the other hand, a polishing head elevating means for vertically moving up and down; and an arm oscillating means for oscillating the arm in a horizontal plane; the platen rotation driving means and the polishing head rotating means are sealed in the outer periphery. It is installed in.

[0007]

According to the present invention, since the rotation driving means of the surface plate and the polishing head are arranged so that the outer periphery is sealed, the dust generated by these rotation driving is scattered around the polishing apparatus. Contamination of the work and atmosphere is prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. A surface plate 11 having a polishing cloth 11a on its surface is rotatably attached to the frame 10 by bearings 12 and 13. The open end of the frame 10 is the seal member 1
It is sealed by 4. A rotor 16 forming a surface plate motor M1 is attached to a shaft 15 of the surface plate 11, and a stator 17 paired with the rotor 16 is attached to the frame 10 side to form a so-called built-in type motor M1. . A rotary encoder 18 for detecting the number of rotations is connected to the lower end of the shaft 15.

On the frame 10, a turning motor M2 is erected on the left side of the surface plate 11. The cylindrical first column 20 is directly connected to the output shaft of the motor M2. First
The column 20 is attached to the frame 10 by bearings 21 and 22 so as to be rotatable only. Cylindrical protrusion 1
The open end of 0A is sealed by the seal member 23.

A spline groove 24 is provided on the outer peripheral surface of the first column 20, and a ball spline 25 is fitted therein. The ball spline 25 is a hollow cylindrical second column 2
6 is fixed in the second column 26 to the first column 2
It is attached so that it can move up and down with respect to 0. Reference numeral 27 is a key for preventing relative rotation of the ball spline 25 and the second column 26. The second column 26 is formed to have a length that can cover the exposed portion above the seal 23 of the first column 20 over substantially the entire length, and when the lower end thereof is located near the lower limit shown in FIG. The cylindrical protrusion 10 </ b> A of the frame 10 supporting 21 is covered.

At the upper end of the first column 20, a piston rod 31 of an air cylinder 30 as a lift drive unit is fixed via a load cell 32 as a load sensor. The upper end of the second column 26 is connected to the air cylinder 30 via the connecting cylinder 33. The upper end of the first column 20 is covered by the second column 26, the connecting cylinder 33, and the air cylinder 30.

An arm 34 is integrally provided on the upper portion of the second column 26. The arm 34 is located above the surface plate 11, and a polishing head 40 is attached to the arm 34 so as to face the surface plate 11. The polishing head 40 is attached to the lower end of a shaft 42 via a universal joint 41, and the shaft 42 is mounted on the arm 3 via bearings 43, 44 and a casing 45.
4 is rotatably attached. Also casing 45
The open end of is sealed by a seal member 46.

A rotor 47 which forms the polishing head motor M3 is attached to the shaft 42, and a stator 48 which is paired with the rotor 47 is attached to the casing 45 side to form a so-called built-in type motor M3. . A rotary encoder 49 for detecting the number of rotations is connected to the upper end of the shaft 42.

A high-resolution type optical scale 50 is mounted inside the connecting tube 33 along the vertical direction, and a reading head 51 is mounted on the upper end of the first column 20.

Next, the operation of this apparatus will be described. When the air cylinder 30 is actuated and the piston rod 31 is projected, the air cylinder 30 rises, whereby the second column 26 rises along the first column 20 by the ball spline 25 via the connecting cylinder 33, The polishing head 40 attached to the arm 34 is moved upward. A work W such as a semiconductor wafer is attached to the lower surface of the polishing head 40 in a raised state.

Next, the air cylinder 30 is operated to lower the connecting cylinder 33. The second column 26 is moved by the ball spline 25 by the lowering of the connecting cylinder 33.
1 along the spline groove 24, and the polishing head 40 is lowered as shown in FIG. By this lowering, the surface (the lower surface in FIG. 1) of the work W held by the polishing head 40 is brought into contact with the polishing cloth 11 a on the surface plate 11.

The pressing force of the work W against the polishing cloth 11a is the load cell 32 provided at the lower end of the piston rod 31.
Is controlled and the pressure of the pressurized air supplied to the air cylinder 30 is controlled by a control device (not shown) to set and control to an appropriate value.

Next, the motors M1 and M3 are operated, and the signals from the rotary encoders 18 and 49 cause the motors M1 and M3 to rotate at a predetermined number of revolutions, whereby the surface plate 11 and the polishing head 40 are rotated at a predetermined speed. Rotate with. At this time, a polishing liquid is supplied to the polishing cloth 11a on the surface plate 11, but since this is the same as a known one, illustration and description thereof will be omitted in this embodiment.

While pressing the work W against the polishing cloth 11a,
The turning motor M2 is actuated to reciprocally rotate the first column 20 at a predetermined speed over a predetermined angular range. As a result, the arm 34 reciprocates, the polishing head 40 is reciprocally moved along the upper surface of the surface plate 11 in the radial direction passing through substantially the center, and the surface of the work W is polished by the polishing cloth 11a.

At this time, the surface plate 11 and the polishing head 40 are rotated, and the first column 20 is rotated, that is, the polishing head 4 is rotated.
For the turning of 0, the motors M1, M directly connected or built-in without interposing a rotation transmission mechanism such as a belt or a gear.
2 and M3, dust is hardly generated, vibration is hardly generated, and highly accurate polishing is performed.

The up-and-down moving part that is likely to generate dust is in the second column 26 separated from the surface plate 11, and the second column 2
6, because it is covered by the connecting cylinder 33 and the air cylinder 30, even if dust is generated from this vertical movement part, the work W
Is unlikely to be polluted, and the release of this dust into the atmosphere is suppressed. In order to suppress the release of dust into the atmosphere more completely, the connecting cylinder 33
It is preferable that air be circulated by actively exhausting air from each space such as inside.

As the polishing amount of the work W, the detection value of the reading head 51 of the optical scale 50 at the start of polishing is stored in the control device, and the amount of lowering of the second column 26 from this value, that is, the polishing head 40. It is detected by detecting the amount of descent by the position measuring device including the optical scale 50 and the reading head 51. This polishing amount can be measured with a minimum unit of 0.05 μm if the high-resolution type optical scale 11 is used, but not limited to the optical scale 11, various measuring devices such as a laser interferometer are used. It is possible.

When the polishing amount reaches a desired value, the control device causes the air cylinder 30 to control the second column 26 and the arm 3.
The polishing head 40 is raised via 4 and the polishing is completed.

FIG. 2 is a vertical sectional view showing a second embodiment of the present invention. The present embodiment differs from the above-described embodiments in that the drive mechanism for moving the polishing head 40 up and down is directly installed above the polishing head 40. Other than that, the same structures as those of the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Hollow casing 4 fixed to the arm 34
A hollow shaft 52 is rotatably supported in the shaft 5 by a bearing 44 coaxially with the hollow casing 45. A spline 54 is formed on the inner peripheral surface of the hollow shaft 52, and a spline shaft 56 having a spline that engages with the spline 54 is axially slidably inserted.

At the lower end of the spline shaft 56, the universal joint 4
The polishing head 40 is connected via 1 and the upper and lower ends thereof are rotatably supported by bearings 43 and 53.

The support bearing 43 on the lower end side is held in a bearing cover 57 suspended below the hollow casing 45 by a bellows cover 55 which also serves as a dustproof cover. Further, the support bearing 53 on the upper end side is a bearing that can also support a thrust load, and is held in a hollow cylindrical bearing cover 58 attached to the lower portion of the piston rod 31 of the air cylinder 30 via the load cell 32. There is.

The air cylinder 30 has a hollow casing 45.
The piston rod 31 is fixed to the upper end of the so as to be coaxial with the spline shaft 56.

An optical scale 50 is vertically mounted on the inner surface of the upper portion of the hollow casing 45, and a reading head for reading the optical scale 50 is mounted on a bearing cover 58 mounted on the lower portion of the piston rod 31. 51 is fixed.

According to this embodiment having such a structure, the polishing head 40 includes the spline shaft 56 and the hollow shaft 52.
It is rotationally driven by a motor M3 via. Further, by operating the air cylinder 30 and moving the piston rod 31 up and down, the spline shaft 56 is directly moved up and down via the bearing cover 58, and the polishing head 40 moves up and down. Other functions are similar to those of the above-described embodiment.

In this embodiment, since the air cylinder 30 for driving the polishing head 40 up and down is directly connected to the upper portion of the polishing head 40, the required driving force of the air cylinder 30 is reduced as compared with the above-described embodiments. It is possible to downsize the device. Further, since the polishing head 40 is directly moved up and down without moving the arm 34 up and down, it is easy to control the up-and-down position and the polishing accuracy can be improved.

Further, the spline shaft 56 is attached to the dustproof cover 55.
Since it is covered with, fine powder is prevented from entering the sliding portion of the spline shaft 56 during polishing work, and
Fine powder generated from the motor M3 and other rotating and sliding parts is prevented from falling on the surface plate 11.

In the above-described embodiment, the built-in type motors M1 and M3 are used as the rotation driving motors for the surface plate 11 and the polishing head 40.
A separate motor is used for the shaft 1
Similar effects can be obtained by directly connecting to 5, 42. In addition, the lifting drive unit of the polishing head 40 is the air cylinder 3
Not limited to 0, various drive devices such as hydraulic type and electric type servo motors can be used. Furthermore, although the above-described embodiment shows a single-side polishing apparatus that polishes only the surface (lower surface) of the work W, the present invention is not limited to this, and by using an upper surface plate as the polishing head 40, a double-side polishing apparatus can be used. Is also applicable.

FIGS. 3 and 4 are views showing a third embodiment of the present invention. In this example, at the end of polishing, the polishing liquid remaining in the polishing liquid receiver was dried and solidified,
A preventive device is provided to prevent dust from scattering.

That is, on the outer peripheral side of the lower frame 10 of the polishing apparatus, a frame body 62 is installed so as to surround the lower frame 10, and a ring-shaped table is provided at a position slightly higher than the surface plate 11 at the upper end of the frame body 62. 60 is fixed horizontally.
A gutter-shaped polishing liquid receiver 61 is attached to the inner peripheral portion of the table 60 along the outer circumference of the surface plate 11.

On the inner periphery of the table 60, the surface plate 11
A cleaning water supply pipe 65 having a large number of small holes 66 is arranged along the outer circumference of the cleaning water 63, and the cleaning water 63 supplied from a cleaning water supply source (not shown) is received by the polishing liquid receiver. It is made to flow out into 61. Further, a guide piece 64 inclined downward is attached to the peripheral edge of the upper surface of the surface plate 11. A discharge port (not shown) is provided at the bottom of the polishing liquid receiver 61.

According to this embodiment, after the polishing process is completed, the flow path of the polishing liquid is switched to the cleaning water supply flow path, and further,
The cleaning water is supplied to the pipe 65 from the cleaning water supply source.

These cleaning water flows along the inner surface of the polishing liquid receiver 21 to wash away the polishing liquid adhering to or remaining on the inner surface of the polishing liquid receiver 21, discharge it from the discharge port, and slightly remain thereafter. To prevent the polishing liquid from drying.

As a result, the polishing liquid is prevented from drying and solidifying after the polishing process is completed, and the polishing powder contained in the polishing liquid does not fly up as dust.

[0040]

As described above, according to the present invention, the dust generated by the device can be suppressed, the work being polished is less contaminated by the dust, and the dust entering the atmosphere can be reduced. Since it is less likely to be emitted, it can be used in a clean room, and further, it is possible to obtain the effect of suppressing the occurrence of vibration and performing highly accurate polishing.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 3 is a side view including a partial cross section showing a third embodiment of the present invention.

FIG. 4 is a partially enlarged perspective view showing a main part of the third embodiment.

[Explanation of symbols]

 11 surface plate 18 rotary encoder 20 first column 25 ball spline 26 second column 30 air cylinder (elevating drive unit) 32 load cell 33 connecting cylinder 34 arm 40 polishing head 49 rotary encoder 50, 51 position measuring device 61 polishing liquid receiver 65 cleaning Water supply pipe

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshio Oishi 2068 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd. Numazu Office

Claims (8)

[Claims] 1. A polishing platen horizontally arranged; a platen rotation driving means for rotatingly driving the platen; a polishing head rotatably arranged above the platen so as to face the platen. An arm for rotatably supporting the polishing head; a polishing head rotation driving means for rotatably driving the polishing head; a polishing head elevating means for vertically moving the polishing head with respect to a surface plate; And an arm revolving means for revolving in a horizontal plane, wherein the platen rotation driving means and the polishing head rotating means are arranged in a state in which the outer periphery is sealed. 2. The polishing apparatus according to claim 1, wherein the surface plate rotation driving means and the polishing head rotation means include motors directly connected to the surface plate and the polishing head, respectively. 3. The polishing apparatus according to claim 2, wherein the directly connected motor is a built-in type motor. 4. The arm swinging means is erected on the side of the surface plate and is rotatably mounted around a rotation axis parallel to the rotation axis of the surface plate, and an outer periphery of the first column. 2. The polishing apparatus according to claim 1, further comprising a second column engaged with the arm so as to be capable of transmitting rotation and holding the arm in a horizontal direction, and a first column rotation driving means for rotating the first column. 5. The polishing apparatus according to claim 4, wherein the first column rotation driving means includes a motor directly connected to the first column. 6. The polishing apparatus according to claim 1, wherein the polishing head elevating means is connected to an upper portion of the polishing head. 7. The polishing apparatus according to claim 1, wherein the polishing head raising / lowering means is disposed above the first column and raises / lowers the second column along the first column. 8. The polishing apparatus according to claim 1, wherein a polishing liquid receiving member is arranged at a position below the outer periphery of the surface plate, and cleaning water can be continuously supplied into the polishing liquid receiving member.